Shell is nearing the sale of its fuel stations in South Africa to a unit of Abu Dhabi’s biggest oil company in a deal valued at about $1-billion, according to people familiar with the matter. Shell and the retail arm of Abu Dhabi National Oil Co. are preparing to announce an agreement in the coming days, the people said, asking not to be identified as the matter is private. A transaction would give the Middle Eastern company control over 600 retail fuel outlets, or about 10% of the market in Africa’s biggest economy, adding to Adnoc’s deal spree as it expands globally.